Device with an air intake manifold and an air mass sensor arrangement inserted therein

ABSTRACT

The invention relates to a device with an air inlet manifold ( 1 ) and an air mass sensor arrangement ( 2 ) inserted radially therein, the insertion opening ( 3 ) of which is arranged perpendicular to the airflow direction ( 6 ) in the manifold ( 1 ). A wing-shaped shielding body ( 7 ) is arranged before the insertion opening ( 3 ) such as to cover the insertion opening ( 3 ) and guarantee a streamline airflow to the insertion opening ( 3 ) and the essentially straight surface thereof, transverse to the flow direction of the air flowing over said surface, is oriented perpendicular to the insertion direction of the air mass sensor arrangement ( 2 ).

CLAIM FOR PRIORITY

This application claims priority to International Application No.PCT/DE02/04085, which was published in the German language on May 15,2003, which claims the benefit of priority to German Application No. 10154 253.4, which was filed in the German language on Nov. 5, 2001.

TECHNICAL FIELD OF THE INVENTION

The present invention relates to a device having an intake manifold andan air mass sensor arrangement.

BACKGROUND OF THE INVENTION

In internal combustion engines, with increasing frequency, cases havebecome known in which relatively large quantities of water have passedinto the air intake duct. Air mass sensors usually based on hot-filmmanometry are normally arranged in the intake manifold in the air intakeduct. In these air mass sensors, considerable distortion of themeasuring signal or even failure of the sensor occurs in the event ofthe sensor element coming into contact with water.

The actual air mass sensors are accommodated in an air flow passage ofan air mass sensor arrangement. EP 0 908 704 A1 shows an example of anair mass sensor arrangement which is inserted in an intake manifold ofan internal combustion engine and in which the air flow passage in thesensor arrangement runs essentially perpendicularly to the air flowdirection in the intake manifold, a factor which may be regarded as afirst step in avoiding contact of the sensor element with water;however, this step is not nearly adequate. The air inlet opening of thesensor arrangement is oriented perpendicularly to the air flow directionin the intake manifold and is designed to be of relatively large area inorder to even out flow fluctuations, which would distort the sensorsignal. However, water is increasingly caught by the large-area inletopening, a factor which again modifies the effect of the curveddirection of the flow passage.

A device with an air intake manifold and an air mass sensor arrangementinserted radially therein, in which device a shielding body is arrangedupstream of the inlet opening of the air mass sensor arrangement, can begathered from the product specification of an air mass sensor fromPierburg AG, which according to the history listed there is supposed tobe resistant to water and particles. The shielding body, on the onehand, covers the inlet opening, so that no water particles can passdirectly into the inlet opening, and, on the other hand, appears to beof streamlined design, so that the air flow nonetheless reaches theinlet opening. It is at the same time designed to be rectilinear in theflow direction transversely to the curved profile of its surface and isarranged in the intake manifold in such a way that the direction of thisrectilinear profile is parallel to the insertion direction of the airmass sensor arrangement.

According to the description with regard to a diagram on page 4 of theproduct specification, a water flow of 2.5 ml/min is taken as a basis,which can easily be coped with by the device shown. However, water flowsof over 200 ml/min often occur in practice, and the device shown wouldprobably hardly be able to cope with these water flows, since a largenumber of water particle ricochets can pass into the inlet opening ofthe air mass sensor arrangement.

DE 10015918A1 discloses a device for determining at least one parameterof a medium flowing in a line, this device having an air pipe into whicha mass sensor arrangement is inserted radially. In the flow directionupstream of the measuring arrangement, a deflecting grid is arranged inthe intake manifold, this deflecting grid directing the flowing air ontoa baffle mound which is integrally formed in the interior of the intakemanifold and is arranged between the grid and the measuring arrangement.

DE19632198C1 discloses a device for measuring the mass of a flowingmedium, this device having an air flow pipe and a measuring arrangementwhich is inserted radially into the air flow pipe. Arranged upstream ofthe measuring arrangement is a baffle body whose longitudinal extentruns in a direction parallel to the insertion direction of the measuringarrangement in the air pipe.

DE1001642A1 discloses a device for determining at least one parameter ofa flowing medium, this device having an air flow pipe in which ameasuring arrangement is inserted in the radial direction. Furthermore,this device has a deflecting body which is arranged upstream in the flowdirection and whose longitudinal extent runs parallel to the insertiondirection of the sensor arrangement in the intake manifold. The task ofthe baffle body is to produce flow separation at sharp-edged corners.Arranged between the disturbance body and the measuring arrangement is aguide body which is intended to feed partial air flows to the measuringarrangement in a defined manner.

SUMMARY OF THE INVENTION

The present invention discloses a device which is designed such thatvirtually all the water particles can be kept away from the inletopening.

In one embodiment of the invention, the device is formed with an airintake manifold and an air mass sensor arrangement which is insertedradially therein and whose inlet opening is oriented perpendicularly tothe air flow direction in the intake manifold, a wing-shaped shieldingbody being arranged upstream of the inlet opening in such a way that itcovers the inlet opening on the one hand and ensures a non-separatingair flow to the inlet opening on the other hand, and its essentiallyrectilinear surface running transversely to the flow direction of theair flowing over its surface is oriented perpendicularly to theinsertion direction of the air mass sensor arrangement.

Due to this orientation of the fitting direction of the wing-shapedshielding body, it can be of relatively large design, in contrast to theknown shielding body, and can thus keep more water particles awaywithout forming a markedly larger flow resistance, since the additionalarea is located in the flow region of the air mass sensor arrangementlying behind it, which already produces a flow resistance.

Especially advantageous with this fitting direction, however, is thecontribution of the positive pressure, due to the air mass sensorarrangement, at its inflow side, this positive pressure, in addition tothe wing-shaped and thus streamlined configuration of the shieldingbody, helping to ensure that the flow to the inlet opening does notseparate, so that a low signal noise level is achieved.

The designation “wing-shaped” refers to shapes which, as already stated,are streamlined and have leading edges which enable the flow to comeinto effective contact with the shielding body without separating underswirl formation. The leading edges are preferably rounded off or beveledin such a way that the air flow and the leading edge form an acuteangle. The further profile of the shielding body may in principle berectilinear, but it is advantageous if it has a slight curvature orarching.

Although the shielding body may be thicker in the region of the leadingedge, like an aircraft wing, it is advantageous for production reasonsif it has an essentially constant thickness, since it is produced in anadvantageous manner as an injection molding. In an especiallyadvantageous manner, it is formed in one piece with the intake manifold,a factor which allows very cost-effective production.

In an especially advantageous design of the device according to theinvention, the margins of the shielding body which run in the flowdirection are provided with walls which may be provided both on the topside and on the underside or also on both sides. They may run over theentire length of the shielding body or also only in sections. These sidewalls ensure that fewer marginal swirls are generated, so that it ispossible to provide a narrower shielding body, which produces lesspressure loss in the intake manifold on account of a lower flowresistance.

In addition, the side walls provide protection against water dropletspassing by means of the flow separated at the margins of the shieldingbody or as ricochets into the inlet opening of the air mass sensorarrangement.

The flow separation edge of the shielding body, with regard to the flowdirection of the air in the intake manifold, lies below the inletopening of the air mass sensor arrangement, since this inlet openingshould be shielded as completely as possible. In addition, in anespecially advantageous design of the invention, it lies downstream ofthe inlet opening with regard to the flow direction in order to preventwater particles possibly snatched up at the separation edge from passinginto the inlet opening.

The wing-shaped shielding body is provided with holders at its fourcorners, by means of which holders it is connected to the intakemanifold—advantageously in one piece. In this case, it is especiallyadvantageous for production reasons if the front holders and the rearholders are laterally offset from one another, so that the intakemanifold with the shielding body can easily be demolded during theinjection molding.

The holders of the shielding body which lie close to the air mass sensorarrangement are advantageously arranged obliquely to the flow direction,so that the air flow is brought together again downstream of the airmass sensor arrangement.

In an advantageous design of the invention, the front holders, at theirtrailing edge, run obliquely to the direction of the air flow, so thatwater droplets forming at the holder can run at this trailing edge withthe flow away from the inlet opening and cannot be separated andpossibly directed with the flow to the inlet opening.

In an advantageous embodiment of the invention, that side of the airmass sensor arrangement which is oriented toward the shielding body hasa transversely running web or a transverse groove, so that the waterstriking this side of the sensor arrangement cannot run to the inletopening.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is explained in more detail below with reference toexemplary embodiments and with the aid of the figures. In the drawings:

FIG. 1 shows a longitudinal cross section of a device according to theinvention.

FIG. 2 shows a perspective representation of the device according toFIG. 1 as viewed in the flow direction.

FIG. 3 shows a perspective representation of the device according toFIG. 1 as viewed against the flow direction.

DETAILED DESCRIPTION OF THE INVENTION

The exemplary embodiment shown in the figures of a device according tothe invention shows an inlet manifold 1, into which an air mass sensorarrangement 2 is inserted radially. In its essential parts, the air masssensor arrangement 2 is constructed in a similar manner as disclosed byEP 0 908 704 A1 and need not be described in detail here. It has aninlet opening 3 and an outlet opening 4. The flow passage 5 between theinlet opening 3 and the outlet opening 4 has a curved configurationrunning essentially perpendicularly to the flow direction (indicated byan arrow 6) of the air in the intake manifold 1, as can be seen fromFIG. 1, so that impingement of water particles on the actual sensorelements (not shown) is already reduced by this measure.

Relative to the flow direction of the air in the intake manifold 1, ashielding body 7 is arranged upstream of the inlet opening 3. It isdimensioned in such a way that its projection onto the inlet opening 3completely covers the latter. Furthermore, in the flow direction of theair, it has a curved, wing-shaped profile of virtually constantthickness. Due to this configuration of the shielding body 7, waterparticles entrained with the intake air are prevented from passing intothe inlet opening 3. However, the wing-shaped and thus streamlinedconfiguration of the shielding body 3 ensures that the air flow isdirected along the shielding body to the inlet opening withoutseparation; the water particles continue to fly straight ahead onaccount of the larger mass.

The leading edge 8 of the shielding body 7, in the example shown, isbeveled in such a way that it forms an acute angle with the air flow. Asa result, the air flow can come into effective contact and does notseparate. Alternatively, the leading edge 8 may also be of round design.It is likewise not necessary for the shielding body 7 to have a constantthickness; it could also be thicker in the region of the leading edge 8,that is to say it could have the overall cross section of an aircraftwing. It is essential that it permits a non-separating air flow to theinlet opening 3.

The generation of this non-separating flow is additionally intensifiedby the orientation according to the invention of the shielding body 7relative to the air mass sensor arrangement 2. A positive pressure isproduced by the air mass sensor arrangement 2 in its air intake region,this positive pressure directing the inflowing air together with thewing-shaped shielding body 7 to the inlet opening 3.

The shielding body 7 is connected to the intake manifold 1, preferablyin one piece, by means of two front holders 9 and two rear holders 10.The front holders 9 and the rear holders 10 are arranged laterallyoffset from one another, so that the device can easily be demoldedduring the production by means of injection molding technology. The rearholders 10 are oriented obliquely toward the center of the intakemanifold, so that the air flow is brought together again downstream ofthe air mass sensor arrangement 2. The trailing edge 11 of the frontholders 9 runs obliquely to the air flow direction 6 toward the intakemanifold 1 in order to direct water droplets forming there away from theinlet opening 3.

The separating edge 12 of the shielding body 7 is positioned below theinlet opening 3 of the air mass sensor arrangement 2 and preferablydownstream of the latter, so that no water particles swirled up at thisedge 12 can pass into the inlet opening 3.

In the advantageous design shown in the figures of the device accordingto the invention, side walls 13, 14 are advantageously integrally formedon the margins of the shielding body 7, these side walls 13, 14preventing a separation of the air flow at these edges or the ingress ofwater particle ricochets and thus permitting a narrower shielding body 7which has a lower flow resistance. The side walls may be provided bothon the top side of the shielding body 7 as top side walls 13 and on itsunderside as bottom side walls 14. They may be integrally formed on themargins of the shielding body 7 over the entire length of the latter,like the top side walls 13, and also only in one section, like thebottom side walls 14.

In the exemplary embodiment shown in the figures, a transverse groove 15is provided on that side of the air mass sensor arrangement 2 which issubjected to the air flow in the intake manifold 1.

Alternatively, it is equally possible to provide a transversely runningweb. These measures prevent water particles which strike this side ofthe air mass sensor arrangement 2 from passing into the inlet opening 3.

1. A device, comprising: an air intake manifold and an air mass sensorarrangement which is inserted radially therein and whose inlet openingis oriented perpendicularly to an air flow direction in the intakemanifold; a shielding body being arranged upstream of the inlet openingsuch that its projection onto the inlet opening covers the inletopening, wherein the shielding body is wing-shaped and ensures anon-separating air flow to the inlet opening, and has an essentiallyrectilinear surface running transversely to a flow direction of the airflowing over its surface and is oriented perpendicularly to an insertiondirection of the air mass sensor arrangement.
 2. The device as claimedin claim 1, wherein the shielding body has an arched profile along theflow direction of the air flowing over its surface.
 3. The device asclaimed in claim 1, wherein margins of the shielding body which runessentially in the flow direction of the air flowing in the intakemanifold are provided with side walls which laterally define a top sideand/or underside of the shielding body for avoiding marginal swirls. 4.The device as claimed in claim 1, wherein a leading edge of theshielding body, the leading edge being oriented in the flow direction ofthe air flowing in the intake manifold, is beveled or rounded off, sothat the air flow makes effective contact.
 5. The device as claimed inclaim 4, wherein the edge of the shielding body which is oriented the inflow direction of the air flowing in the intake manifold lies under theinlet opening of the air mass sensor arrangement and downstream of theinlet opening relative to the air flow direction.
 6. The device asclaimed in claim 1, wherein the shielding body is formed in one piecewith the intake manifold.
 7. The device as claimed in claim 1, whereinthe shielding body has four corners and has holders at the four corners,and front holders and rear holders are arranged laterally offset fromone another.
 8. The device as claimed in claim 7, wherein the rearholders are arranged obliquely to the air flow direction such that theair flow is directed toward a center of the intake manifold.
 9. Thedevice as claimed in claim 7, wherein the front holders, at a trailingedge, run obliquely to the air flow direction toward a wall of theintake manifold.
 10. The device as claimed in claim 1, wherein atransversely running web or a transverse groove is provided on the airinflow side of the air mass sensor arrangement, so that water strikingthe sensor arrangement side cannot run to the inlet opening.